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M Shiraishi

Publications and source records attributed to M Shiraishi.

At least 55 records · Page 3Linked to original sources
PubMed2000

Characteristics of collagen-induced Ca2+ mobilization in bovine platelets.

We characterized the collagen-induced increase in cytosolic Ca2+ ([Ca2+]i) of bovine platelets loaded with the Ca2+ indicator Fura-PE3/AM. Collagen (10 micrograms/ml)-induced increase in [Ca2+]i was only partially inhibited by aspirin, a cyclooxygenase inhibitor, or adenosine 3'-phosphate 5'-phosphosulfate (A3P5PS, a P2Y1 receptor antagonist), while in human platelets it was almost completely suppressed by aspirin. Collagen-induced increase in [Ca2+]i of bovine platelets was inhibited by U73122 (0.3-5 microM), a phospholipase C inhibitor. Collagen (10 micrograms/ml) increased production of inositol 1,4,5-trisphosphate, which was prevented by pretreatment with U73122 (5 microM). Collagen (10 micrograms/ml) accelerated Mn2+ entry, since the rate of Fura-PE3 quenching by Mn2+ was enhanced by 13-fold following stimulation with collagen. U73122 inhibited the acceleration of Mn2+ entry induced by collagen. PGE1 (2.5 microM) partially inhibited the collagen (50 micrograms/ml)-induced increase in [Ca2+]i in bovine platelets but not in human platelets. The data suggest that collagen-induced Ca2+ mobilization in bovine platelets is mediated by phospholipase C. The Ca2+ mobilization in bovine platelets is different from that in human ones as to the dependency on arachidonic acid metabolites and sensitivity to PGE1.

Adenosine Diphosphate↗
PubMed2000

In situ perfusion of the liver enhances the efficiency of retrovirus-mediated gene transfer to hepatocytes.

To increase the efficiency of retrovirus-mediated gene transfer targeting an individual's liver in vivo, the liver was perfused in situ with the retrovirus vector during hepatic cold ischemia. Four weeks prior to gene transfer, the spleen was transpositioned to the left subcutaneous position to develop a portosplenic shunt, which was performed in order to prevent intestinal congestion during hepatic ischemia. Traditional retrovirus vectors (1 x 10(5) CFU/ml) which encode genes for the Escherichia coli beta-galactosidase (LacZ) were used in this study. Twenty-four hours after partial hepatectomy (70%), the remnant liver was surgically isolated, perfused with 1 ml of vector solution through the portal vein, and kept in contact with the vector for 30 min under cold ischemia (group 1). Hepatic ischemia could thus be performed without any intestinal congestion, due to the preestablished portosystemic shunt. In group 2, the liver was perfused with 1 ml of vector solution through the portal vein without in situ perfusion of the liver. Animals were sacrificed 1, 3, 7 and 28 days after gene transfer. In X-gal staining, the transferred LacZ was detected positive in 10-15% of the hepatocytes only in group 1, 3 days after gene transfer. Graft histology and a liver function test showed no difference between both groups 24 h after gene transfer. In conclusion, in situ perfusion of the liver greatly enhanced the efficacy of retrovirus-mediated gene transfer, targeting an individual's liver in vivo.

Animals↗
PubMed2000

Migrating site of bleeding in a right colon demonstrating angio-dysplasia following a segmental resection of the colon. A unique variant of angiodysplasia.

BACKGROUND/AIM: A case of angiodysplasia of the right colon presenting with a migrating site of bleeding following a segmental resection of the colon in a 38-year-old Japanese is herein reported. METHODS: The case records of a patient with severe intestinal bleeding and multiple surgeries were reviewed, and then the histologic features were compared with the operative findings. The patient received many units of packed red blood cells and had also undergone three segmental colectomies and most recently a curative ileocolostomy. Despite an exhaustive evaluation, the bleeding sites could not be detected clinically. RESULTS: Ectatic, tortuous submucosal veins were presented in four sections of the colon (cecum, ascending colon and transverse colon, respectively) out of a total of 30 sections that were examined. These veins pierced the proper muscle layer of the colon, but did not traverse the muscularis mucosa. Our case of segmental microscopic angiodysplasia may represent a previously unreported unique variant, because the angiodysplastic lesions were present in the segmental colon and they developed bleeding from the distal remnant colon immediately after each segmental colectomy until an extended right hemicolectomy containing the oral part of the descending colon was done. In spite of the severe bleeding, the mucosa of the colon appeared to be essentially normal during a macroscopic inspection. CONCLUSION: Gastrointestinal bleeding from angiodysplasia is generally assumed to arise from macroscopically visible vascular lesions within the mucosa. However, angiodysplastic lesions are often unrecognizable and multiple in the gastrointestinal tract, and especially tend to affect both the cecum and ascending colon. When this disease process is recognized, a subtotal colectomy may thus be called for to control bleeding.

Adult↗
PubMed2000

Combined endoscopic and surgical treatment for multiple polyps of the small intestine in Peutz-Jeghers syndrome: a case report.

Combined endoscopic and surgical treatment in a 14-year-old girl with Peutz-Jeghers syndrome is reported herein. The patient was diagnosed with Peutz-Jeghers syndrome because of mucocutaneous pigmentation and hamartomas of the small intestine at 10 years of age, when she underwent an emergency laparotomy for an intussusception of the small intestine. Since this diagnosis, she has undergone follow-up, and barium radiologic and endoscopic studies have shown multiple polyps of various sizes from the stomach throughout the small intestine and to the colon. This time, with the use of combined endoscopic and surgical treatment for polyps of the small intestine, 26 polyps were removed endoscopically by performing only one enterotomy. This combined technique may allow for a longer interval between laparotomies, therefore reducing the complications associated with multiple laparotomies and resections.

Adolescent↗
PubMed1999

Analysis of Fas system in pulmonary injury of graft-versus-host disease after rat intestinal transplantation.

The lung is one of the primary targets of acute graft-versus-host disease (GVHD), which is the principal complication that occurs after allogeneic intestinal transplantation. The purpose of this study is to investigate the involvement of Fas/Fas ligand system in pulmonary injury after rat semi-allogeneic intestinal transplantation. The lungs were serially harvested from LEW x BN F1(LBNF1) recipients of either LEW heterotopic intestinal allografts or LBNF1 isografts, on days 1, 3, 5, 9, and 13 posttransplant. In light microscopy, pulmonary injury became apparent on day 13 in the allogeneic combination, showing a thickening of the alveolar septa. The incidence of apoptosis, examined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) biotin nick end-labeling, was observed to increase steadily in the alveolar cells accompanied by a progression of GVHD. In an immunohistochemical study, Fas was constitutively expressed in the lung, although Fas ligand was expressed most extensively on day 9. The immunoreactivity of both Fas and Fas ligand were observed in alveolar cells, in addition to leukocytes. An analysis by reverse transcription polymerase chain reaction also revealed that the expression of Fas mRNA was constitutive without any significant change, although that of Fas ligand mRNA increased substantially and peaked on day 9, which was significant compared to the isogeneic combination. In conclusion, transcriptionally up-regulated Fas ligand and increased number of apoptosis suggests that the Fas system may play a role in the pathophysiology of GVHD-induced pulmonary injury.

Animals↗
PubMed1999

Stable gene expression with VSV-G pseudotyped-retrovirus vector in the rat liver.

BACKGROUND: Pseudotyped-retrovirus-mediated gene transfer to the regenerating rat liver was investigated in vivo and the findings were compared with those for retrovirus-mediated gene transfer. MATERIALS AND METHODS: Four weeks prior to gene transfer, the spleen was transpositioned to the left subcutaneous position to develop a port-splenic shunt. Twenty-four hours after a partial hepatectomy (68%) was performed, the liver was perfused in situ and kept in contact with either a pseudotyped-retrovirus vector encoding LacZ (7 x 10(7) cfu/ml, Group 1) or a retrovirus vector encoding LacZ (1 x 10(4) cfu/ml, Group 2) for 30 min. The animals were sacrificed at various points after gene transfer, and X-gal staining, reversed polymerase chain reaction (RT-PCR), and ONPG assay were performed to detect the transferred LacZ cDNA. RESULTS: In X-gal staining, the transferred LacZ cDNA started to show a strong beta-galactosidase activity in 30 to 50% of the hepatocytes at 3 days after gene transfer. Positive staining continued to be recognized until 28 days with a slight decrease in its intensity thereafter. On the other hand, Group 2 animals showed weak staining, which was observed in about 10 to 15% of the hepatocytes from 3 days after gene transfer and then decreased thereafter. In RT-PCR, positive mRNA of LacZ was detected constitutively until 28 days after gene transfer in Group 1, whereas two-thirds of the samples showed a negative band in Groups 2 at 3 days after gene transfer. CONCLUSION: In conclusion, the pseudotyped-retrovirus vector was useful in establishing a stable and strong expression of the in vivo gene transfer, while targeting the regenerating liver.

Animals↗
PubMed1999

Analysis of the Fas system and Bcl-2 in rat liver allograft rejection.

BACKGROUND: Apoptosis is involved in the mechanism of cell death observed in liver allograft rejection. The liver cells are sensitive to Fas-mediated apoptosis; however, little is known about the involvement of the Fas system in liver allograft rejection. We used rat models to investigate the expression of Fas/Fas ligand and apoptosis-related proteins during liver allograft rejection. MATERIALS AND METHODS: DA rats to Lewis, and Lewis to Lewis orthotopic liver transplantation were performed; liver samples were collected on days 1, 3, 5, 7, and 9 postoperatively (each n = 3). Apoptosis was monitored by TUNEL and electron microscopy. The expression of Fas, FasL, bcl-2, and bax was examined at the mRNA level and by means of immunohistochemistry. RESULTS: The TUNEL index in the allografts and isografts on day 7 was 20.1 +/- 1.5 and 7.7 +/- 2.6/1000 cells, respectively. Fas and bax mRNA were constitutively expressed in both of the groups. The expression of Fas ligand mRNA in the allografts which rose on day 5 was 10 times stronger compared to that in the isografts. On the other hand, bcl-2 mRNA was generally expressed in the isografts while it decreased in the allografts. The immunohistochemical analysis also showed an increased reactivity of Fas ligand on day 5 in the allograft, which was observed both in parenchymal and nonparenchymal cells. CONCLUSIONS: These results strongly suggest that Fas/Fas ligand interaction mediates the liver injury during allograft rejection. In addition, other regulatory factors of apoptosis, such as bcl-2, might also be involved in this pathogenesis.

Animals↗
PubMed1999

A small-molecule, nonpeptide CCR5 antagonist with highly potent and selective anti-HIV-1 activity.

The beta-chemokine receptor CCR5 is considered to be an attractive target for inhibition of macrophage-tropic (CCR5-using or R5) HIV-1 replication because individuals having a nonfunctional receptor (a homozygous 32-bp deletion in the CCR5 coding region) are apparently normal but resistant to infection with R5 HIV-1. In this study, we found that TAK-779, a nonpeptide compound with a small molecular weight (Mr 531.13), antagonized the binding of RANTES (regulated on activation, normal T cell expressed and secreted) to CCR5-expressing Chinese hamster ovary cells and blocked CCR5-mediated Ca2+ signaling at nanomolar concentrations. The inhibition of beta-chemokine receptors by TAK-779 appeared to be specific to CCR5 because the compound antagonized CCR2b to a lesser extent but did not affect CCR1, CCR3, or CCR4. Consequently, TAK-779 displayed highly potent and selective inhibition of R5 HIV-1 replication without showing any cytotoxicity to the host cells. The compound inhibited the replication of R5 HIV-1 clinical isolates as well as a laboratory strain at a concentration of 1.6-3.7 nM in peripheral blood mononuclear cells, though it was totally inactive against T-cell line-tropic (CXCR4-using or X4) HIV-1.

Amides↗
PubMed1999

Isolation of DNA fragments associated with methylated CpG islands in human adenocarcinomas of the lung using a methylated DNA binding column and denaturing gradient gel electrophoresis.

We have constructed a library of DNA fragments heavily methylated in human adenocarcinomas of the lung to permit the comprehensive isolation of methylated CpG islands in cancer. Heavily methylated genomic DNA fragments from tumors of nine male patients were enriched using a methylated DNA binding column and used for construction of the library. From this library, DNA fragments having properties of CpG islands were isolated on the basis of their reduced rate of strand dissociation during denaturing gradient gel electrophoresis. Approximately 1,000 clones, corresponding to 0.3% of the library were analyzed, and nine DNA fragments were identified as being associated with CpG islands that were methylated in tumor DNA. One CpG island was methylated specifically in tumor DNA, whereas the remaining eight CpG islands were methylated both in normal and tumor DNA derived from the same patients. Our results suggest that the number of CpG islands methylated specifically in tumors is not large. The library, which contains DNA fragments from methylated CpG islands comprehensively, is expected to be valuable when elucidating epigenetic processes involved in carcinogenesis.

Adenocarcinoma↗
PubMed1999

Fas ligand induction in human NK cells is regulated by redox through a calcineurin-nuclear factors of activated T cell-dependent pathway.

Fas ligand (FasL) on cytotoxic lymphocytes is important for mediating apoptosis of activated lymphocytes and other target cells. We have reported that NK cell functions, such as proliferation, cell death, and killing activity, are subject to regulation by cellular redox status. Here, we report that expression of FasL protein and mRNA in activated NK cells is also regulated by redox. Ligation of CD16 on IL-2-preactivated NK cells resulted in reduction of intracellular peroxide level as well as induction of FasL expression. This CD16-induced FasL expression was suppressed by oxidative stress, including thiol deprivation or treatment with hydrogen peroxide (H2O2). Addition of thiol-reducing compounds, such as L-cystine, 2-ME, or N-acetyl cysteine, restored FasL expression. These data suggest that CD16 stimulation requires cellular reducing status for FasL induction in NK cells. Because FasL gene activation following CD16 cross-linking is regulated by the NF of activated T cells (NFAT), we examined the effect of oxidative stresses on NFAT activation. Electrophoretic mobility shift assays revealed that both thiol insufficiency and H2O2 treatment suppressed DNA-binding activity of NFAT and that addition of thiol-reducing compounds reversed or even enhanced it. Furthermore, these oxidative stresses inhibited activity of calcineurin, a serine/threonine phosphatase that regulates NFAT activation. These results suggest that suppression of calcineurin and NFAT activation is a mechanism by which oxidative stress inhibits FasL induction in activated NK cells and further support the hypothesis that thiol-reducing compounds might be required for maintenance of optimal NK functions under physiologic oxidative conditions.

Antibodies, Monoclonal↗
PubMed1999

Activation of stress signaling pathways by the end product of lipid peroxidation. 4-hydroxy-2-nonenal is a potential inducer of intracellular peroxide production.

In the present study, we studied the signal transduction mechanism that is involved in the expression of c-Jun protein evident after exposure of rat liver epithelial RL34 cells to the major end product of oxidized fatty acid metabolism, 4-hydroxy-2-nonenal (HNE). HNE treatment of the cells resulted in depletion of intracellular glutathione (GSH) and in the formation of protein-bound HNE in plasma membrane. In addition, HNE strongly induced intracellular peroxide production, suggesting that HNE exerted oxidative stress on the cells. Potent expression of c-Jun occurred within 30 min of HNE treatment, which was accompanied by a time-dependent increase in activator protein-1 (AP-1) DNA binding activity. We found that HNE caused an immediate increase in tyrosine phosphorylation in RL34 cells. In addition, HNE strongly induced phosphorylation of c-Jun N-terminal kinases (JNK) and p38 mitogen-activated protein kinases and also moderately induced phosphorylation of extracellular signal-regulated kinases. The phosphorylation of JNK was accompanied by a rapid and transient increase in JNK and p38 activities, whereas changes in the activity of extracellular signal-regulated kinase were scarcely observed. GSH depletion by L-buthionine-S, R-sulfoximine, a specific inhibitor of GSH biosynthesis, only slightly enhanced peroxide production and JNK activation, suggesting that HNE exerted these effects independent of GSH depletion. This and the findings that (i) HNE strongly induced intracellular peroxide production, (ii) HNE-induced JNK activation was inhibited by pretreatment of the cells with a thiol antioxidant, N-acetylcysteine, and (iii) H2O2 significantly activated JNK support the hypothesis that pro-oxidants play a crucial role in the HNE-induced activation of stress signaling pathways. In addition, we found that, among the inhibitors of tyrosine kinases, cyclooxygenase, and Ca2+ influx, only quercetin exerted a significant inhibitory effect on HNE-induced JNK activation. In light of the JNK-dependent induction of c-jun transcription and the AP-1-induced transcription of xenobiotic-metabolizing enzymes, these data may show a potential critical role for JNK in the induction of a cellular defense program against toxic products generated from lipid peroxidation.

Aldehydes↗
PubMed1999

Protective effects of ulinastatin against ischemia-reperfusion injury.

We investigated the protective effect of urinary trypsin inhibitor (ulinastatin: UTI) in vitro, in relation to the neutrophil activity in hepatic ischemia/reperfusion (I/R) injury. The rat liver was removed and preserved in cold Ringer's lactate solution for 60 min, followed by 120 min of reperfusion with oxygenated perfusate. The rats were divided into four groups (n = 8 in each group). The livers were perfused with Krebs-Henseleit (K-H) solution containing no additives in group 1, 50,000 U/kg of UTI in group 2, 3.5 x 10(6) of neutrophils in group 3, and both neutrophils and UTI in group 4. In group 3, the AST and ALT levels were always higher than those in other three groups at any point evaluated (P < 0.01) and the LDH levels were observed to be significantly higher than those in other three groups at 0, 5, 10, 60, and 90 min after reperfusion (P < 0. 01). These increase were suppressed by additional pretreatment with UTI in group 4. The bile flow during reperfusion was significantly suppressed in group 3 compared to that of group 4, at both 30 (P < 0. 01) and 60 (P < 0.05) min after reperfusion. The MPO activity after reperfusion in group 3 also significantly increased compared to other three groups (P < 0.01). These data thus suggest that UTI ameliorated the ischemia/reperfusion injury in vitro by inhibiting of neutrophil accumulation in the postischemic liver.

Animals↗
PubMed1999

Early detection of apoptosis and fas ligand expression in hepatic graft-versus-host disease after rat small bowel transplantation.

BACKGROUND: The liver is one of the primary targets of acute graft-versus-host disease (GVHD), which is the principal complication that occurs after allogeneic intestinal transplantation. The purpose of this study is to investigate the involvement of the Fas/Fas ligand system in hepatic GVHD after rat semiallogeneic intestinal transplantation. MATERIALS AND METHODS: Liver samples were serially harvested from LEW x BN F(1) (LBNF(1)) recipients of either LEW heterotopic intestinal allografts (group 1) or LBNF(1) isografts (group 2), on Days 1, 3, 5, 9, and 13 posttransplant. RESULTS: In group 1, hepatic injuries as assessed by either serum aspartate aminotransferase (AST) level, alanine aminotransferase (ALT) level, or cellular infiltration on HE staining became apparent after Day 13. The incidence of apoptosis, examined by terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end-labeling (TUNEL), was observed to steadily increase in the liver from Day 5 accompanied by a progression of GVHD: 17.5 +/- 3.1 and 3.1 +/- 0.4 cells/field (200x) in groups 1 and 2, respectively. In an immunohistochemical study, Fas was constitutively expressed in the liver in both groups, while Fas ligand was expressed most extensively on Day 13 in group 1. Immunoreactivity of both Fas and Fas ligand was observed in hepatocytes, in addition to leukocytes. Analysis by reverse transcription polymerase chain reaction also revealed the expression of Fas mRNA to be constitutive in both groups, while that of Fas ligand mRNA increased significantly from Day 5 and peaked on Day 13 in group 1, and the expression was 10 times stronger than that for isogeneic combination (group 2). CONCLUSION: Early detection of upregulated Fas ligand and increased apoptosis is thus considered to be potentially a useful tool for the diagnosis of hepatic GVHD.

Animals↗
PubMed1999

Bronchoscopic removal of bronchial foreign bodies through the laryngeal mask airway in pediatric patients.

The laryngeal mask airway was used to perform fiberoptic removal of bronchial foreign bodies (peanuts) in two pediatric patients. Laryngeal mask airway offers easy access to the airway, safe respiratory management and direct visualization of the airway during bronchoscopic procedures. Laryngeal mask airway allows the use of larger bronchoscopes than can usually be used for children when bronchoscopy is performed through an endotracheal tube. In each case, the peanuts were removed safely and easily using a Fogarty catheter through the fiberoptic bronchoscope. These cases suggest that laryngeal mask airway is useful in maintaining a secure airway during the removal of bronchial foreign bodies in children.

Bronchi↗
PubMed1999

Characteristics of hepatocellular carcinoma in patients with negative virus markers: clinicopathologic study of resected tumors.

Fifty-one cases of resected hepatocellular carcinoma (HCC) were retrospectively analyzed to evaluate the clinicopathologic features of HCC in patients with negative virus markers. The data were compared between three groups: hepatitis B surface antigen positive (HB, n = 11), hepatitis C virus antibody positive (HC, n = 21), and non-BC (both HbsAg and HCVAb negative, n = 12). Seven patients were excluded from the study because of operative death (n = 3), a history of alcohol abuse (n = 3), or the presence of dual positive HB and HC virus markers (n = 1). The data were analyzed by either an analysis of variance (ANOVA) or a contingency table. The age of the non-BC patients was higher (63.0 +/- 4.1, +/- SE) than that of HB patients (54.0 +/- 3.2, p < 0.05) but was identical to that of the HC group (62.0 +/- 1.8). Among the preoperative laboratory data, the serum glutamic oxaloacetate and glutamate pyruvate transaminoses (GOT, GPT) levels were statistically lower in the non-BC patients (32.8 +/- 4.8 and 28.0 +/- 4.4 IU/L, respectively) than in the HB and HC patients. The pathologic features of the resected specimens in the non-BC patients showed more invasive growth than in specimens from the HB or HC patients. The clinical stages (defined based on the criteria of the Japanese Association of Hepatocellular Carcinoma) were also more advanced in the non-BC patients than in the other groups. Postoperative survival time showed no significant difference among the groups. In conclusion, the non-BC patients had comparatively greater invasive growth and more advanced clinical stages than the HB and HC patients, despite the absence of liver cirrhosis, and so demonstrated the same poor survival data as observed in the HB and HC patients.

Adult↗
PubMed1999

Common bile duct blood clot: an unusual cause of ductal filling defects for calculi.

We report a case of obstructive jaundice caused by a blood clot in the common bile duct in a 75-year-old man with cirrhosis. Five years prior to his admission, he had undergone a left hepatectomy for hepatocellular carcinoma. At the present admission, he appeared icteric, and endoscopic retrograde cholangiography revealed filling defects in the common bile duct. Choledochotomy was therefore performed for possible common duct stones, and exploration of the duct showed blood clot casts filling the duct. The casts were easily removed, and the patient's postoperative course was uneventful. However, he developed ascites and jaundice 1 month later and died of liver failure approximately 3 months after undergoing the choledochotomy. Autopsy revealed hemorrhagic necrosis in the proximal intrahepatic duct of the posterior segment, which was considered to be the cause of the observed hemobilia, as well as the blood clot in the common bile duct at surgery. We report this rare case and discuss the cause of hemobilia.

Aged↗